The evolution of wireless communications and embedded system had lead to a big acceptance of Wireless Sensor Networks (WSNs): network of few to hundreds of thousands of sensor nodes, often with low processing and energy capacities that are capable of physical measurements and ambient monitoring, like temperature, humidity and light. Considering their limited resources it becomes necessary to support mechanisms that ensure rational use of their resources. It is in this context that we examine routing protocols, and show how these can be energy conscious by avoiding nodes with less spare energy. Was evaluated six energy based metrics with the objective to make capable the study of some metrics that they can be used for the routes selection in wireless sensor networks and then verify which of them adjust better to the new context introduced in the routing problem by these networks.